Compressor arrangement

ABSTRACT

The invention relates to a compressor arrangement for compressing a gas. The compressor arrangement comprises a drive unit with a driveshaft that can be driven in rotation and at least one compressor which comprises a compressor casing, at least one gas inlet opening formed in the compressor casing and at least one gas outlet opening formed in the compressor casing and fluidically connected to the at least one gas inlet opening. The compressor also has at least one impeller, which is arranged in the compressor casing, is connected in fixed rotation with the driveshaft and can be driven in rotation, for delivering the gas from the at least one gas inlet opening to the at least one gas outlet opening, and has at least one bearing device for bearing the at least one impeller, wherein the at least one bearing device is arranged on the compressor casing and on the at least one impeller.

This is a U.S. national stage entry of International Patent Application No. PCT/EP2017/062873, filed on May 29, 2017, which claims priority to German Patent Application No. 10 2016 210 464.0, filed on Jun. 14, 2016, the entire contents of all of which are fully incorporated herein by reference.

The invention relates to a compressor arrangement, in particular a side channel compressor arrangement, for compressing a gas, such as air or technical gas.

In known side channel compressor arrangements, the requirements with regard to the manufacturing accuracy of the driveshafts of the drives are extremely high, since the impellers of the compressors are guided into the compressor housings with high precision. An additional difficulty is that the driveshafts generally consist of steel while the compressor housings usually consist of cast aluminum or gray cast iron. The different coefficients of expansion of the materials cause further problems. On the one hand, contact has to be prevented between the impeller and compressor housing. However, on the other hand, excessively large gaps between the impeller and compressor housing result in large pressure drops and thus in reduced efficiency of the compressor arrangement. This problem is even worse when several impellers are arranged on a common driveshaft. Effective sealing of the drive with respect to the gas to be compressed is also often difficult or involves considerable effort. A further drawback is that, if the drive is repaired or replaced, the associated compressor has to be taken apart, since the impeller or impellers thereof is/are carried by the driveshaft of the drive.

The invention is based on the object of overcoming the drawbacks of the prior art and of providing an improved compressor arrangement. In particular, the efficiency of the compressor arrangement is intended to be extremely high and the compressor arrangement is also intended to be particularly easy to assemble/disassemble.

This object is achieved according to the invention by the features specified in claim 1. The essence of the invention is that the at least one bearing apparatus is arranged, in particular directly, on the compressor housing on one side, and, in particular directly, on the at least one impeller on the other side. Expediently, the at least one bearing apparatus sits on the at least one impeller or on at least one impeller bearing surface, while preferably the at least one bearing apparatus sits in the compressor housing or within at least one compressor-housing bearing surface.

The drive is expediently embodied as an electric drive. Other drives are alternatively possible.

The compressor arrangement is a single-stage or multistage compressor arrangement. The at least one impeller is directly or indirectly drive-connected to the driveshaft. The compressor arrangement may comprise a silencer.

The at least one compressor is embodied preferably as a side channel compressor. Accordingly, it has preferably a side channel for conducting and compressing the gas. The at least one impeller then has preferably a multiplicity of impeller blades, which are arranged in the side channel.

Further advantageous configurations of the invention are specified in the dependent claims.

The rolling bearing apparatus according to dependent claim 2 has extremely low frictional resistance, since rolling friction primarily occurs there. Expediently, it has several rolling bodies. It is advantageous for the rolling bodies to be arranged in a cage. The rolling bodies are embodied for example as balls, cylindrical rollers, tapered rollers, spherical rollers, self-aligning rollers, needles or the like. Expediently, the rolling bearing apparatus is capable of absorbing radial and/or axial forces, wherein it is possible at the same time for the at least one impeller to rotate.

The first bearing body according to dependent claim 3 is embodied preferably as an outer body or outer ring, while the second bearing body is embodied preferably as an inner body or inner ring. The outer body surrounds the inner body. It is advantageous for the first bearing body and the second bearing body to be arranged concentrically. The rolling bodies are arranged preferably between the first and second bearing bodies.

The configurations according to dependent claims 4 and 5 indicate once again the decoupling of the at least one bearing apparatus from the driveshaft. Expediently, the internal dimension of the at least one bearing apparatus is between 20% and 150% greater than an outside dimension of an adjacent portion of the driveshaft.

The at least one compressor-housing bearing surface according to dependent claim 6 is expediently annular or cylindrical. It preferably faces the driveshaft or a driveshaft longitudinal center axis.

The at least one impeller bearing surface according to dependent claim 7 is expediently annular or cylindrical. It preferably faces away from the driveshaft or the driveshaft longitudinal center axis. In the assembled state of the compressor arrangement, the at least one compressor-housing bearing surface and the at least one impeller bearing surface of the particular bearing apparatus are preferably arranged concentrically with one another and concentrically about the driveshaft or the driveshaft longitudinal center axis.

The two bearing devices according to dependent claim 8 are expediently arranged in pairs. They are preferably identical.

The at least one coupling device according to dependent claim 9 allows the transmission of rotation and torque from the driveshaft to the coupled impeller. It is expediently embodied separately from the driveshaft and the at least one impeller. Expediently, at least one coupling device is connected, directly or indirectly, to the driveshaft for conjoint rotation in the assembled state. In particular a form-fitting connection, in particular a feather key connection, is provided between the one coupling device and the driveshaft. Expediently, the at least one coupling device is connected, directly or indirectly, to the at least one impeller for conjoint rotation in the assembled state. The at least one coupling device is preferably a multipart coupling device.

According to dependent claim 10, the coupling device is arranged as it were at least regionally within the at least one bearing apparatus.

The magnetic force acting between the at least one coupling device and the at least one impeller, according to dependent claim 12, is achievable for example by magnets, in particular permanent magnets, on the at least one coupling device and the at least one impeller. Alternatively, at least one magnet, in particular permanent magnet, is arranged on the at least one coupling device or the at least one impeller, while the other part is then at least regionally magnetizable.

The seal arrangement according to dependent claim 13 results in a particularly long service life and in extremely high efficiency of the compressor arrangement. It is formed expediently from a flexible sealing material. Preferably, the seal arrangement is embodied as a sealing ring. It is embodied expediently as an axial sealing ring and/or radial sealing ring. It prevents in particular an undesired transfer of gas between the compressor housing and the at least one impeller.

Several preferred embodiments of the invention are described by way of example in the following text with reference to the appended drawing, in which:

FIG. 1 shows a sectional view of a compressor arrangement according to the invention according to a first embodiment,

FIG. 2 shows an exploded view of the compressor arrangement shown in FIG. 1,

FIG. 3 shows a sectional view of a compressor arrangement according to the invention according to a second embodiment,

FIG. 4 shows an exploded view of the compressor arrangement shown in FIG. 3,

FIG. 5 shows a sectional view of a compressor arrangement according to the invention according to a third embodiment,

FIG. 6 shows an exploded view of the compressor arrangement shown in FIG. 5,

FIG. 7 shows a sectional view of a compressor arrangement according to the invention according to a fourth embodiment, and

FIG. 8 shows an exploded view of the compressor arrangement shown in FIG. 7.

A single-stage side channel compressor arrangement, illustrated in its entirety in FIGS. 1 and 2, for compressing a gas comprises a compressor 1 having a compressor housing 2 and a drive 3, which is flange-mounted on the end face of the compressor housing 2.

The drive 3 is embodied as an electric drive. It has a rotationally drivable driveshaft 4, which is rotationally drivable about a driveshaft longitudinal center axis 5. The rotation of the driveshaft 4 is brought about via magnetic forces of the drive 3.

The compressor 1 has an impeller 6 which is arranged in the compressor housing 2, comprises a multiplicity of impeller blades 7 and is connected to the driveshaft 4 for conjoint rotation. The impeller 6 is mounted in the compressor housing 2 in a rotatable or rotationally drivable manner, wherein it is decoupled from the driveshaft 4 in terms of support.

The compressor housing 2 comprises a housing body 8 and a housing cover 9, which are assembled according to FIG. 1 and jointly enclose the impeller 6 with the impeller blades 7.

The housing body 8 has a central first hub 10 with an inwardly facing, cylindrical, first compressor-housing bearing surface 11. The first hub 10 is formed by an annularly extending, first web. Furthermore, the housing body 8 has an annular first side wall 12, which extends radially outwardly from the first hub 10. The first side wall 12 is adjoined externally by an encircling first channel portion 13. The first hub 10, the first side wall 12 and the first channel portion 13 are configured as an integral cast part and together form the housing body 8.

The housing cover 9, which is screwed together with the housing body 8 by means of several connecting screws (not illustrated), comprises a central second hub 14, which is formed in principle in a manner corresponding to the first hub 10. The second hub 14 is formed by an annularly extending, second web and forms a cylindrical, inwardly facing, second compressor-housing bearing surface 15. The second hub 14 is adjoined by a second annular side wall 16, which extends radially outwardly. The second hub 14 is closed axially by a cover body 18. Connected to the outside of the second side wall 16 is an encircling second channel portion 17. The second hub 14, the second side wall 16 and the second channel portion 17, and the cover body 18 are configured as an integral cast part and together form the housing cover 9.

The housing body 8 and the housing cover 9 are connected together such that the two hubs 10, 14 are aligned with one another and the two channel portions 13, 17 jointly delimit a side channel 19 for compressing the gas. The two side walls 12, 16 in this case extend in a manner spaced apart from and parallel to one another. The side channel 19 extends annularly in a spaced-apart manner around a compressor longitudinal center axis 20, which is aligned or coincides with the driveshaft longitudinal center axis 5 in the assembled state of the side channel compressor arrangement.

Formed at the bottom in the housing body 8 is a gas inlet opening 21, which leads into the side channel 19. Also provided in the housing body 8 is a gas outlet opening (not illustrated), which is likewise flow-connected to the side channel 19 and is arranged next to the gas inlet opening 21. The gas inlet opening 21 is expediently adjoined by a gas inlet stub (not illustrated), while a corresponding protruding gas outlet stub (not illustrated) is preferably attached to the gas outlet opening. Between the gas inlet opening 21 and the gas outlet opening, an interrupter (not illustrated) is arranged in the side channel 19.

The impeller 6 is embodied in a single-ring and disklike manner. It comprises a central impeller hub 22, which is formed by two mutually aligned impeller hub bodies 23. Each impeller hub body 23 is formed by an annularly extending web and has an outwardly facing, cylindrical impeller bearing surface 24, which, in the assembled state of the side channel compressor arrangement, extends concentrically with the compressor-housing bearing surfaces 11 and 15. Between the impeller hub bodies 23 there extends a coupling wall 27, which centrally closes the impeller hub 22 and is penetrated by form-fitting cutouts 28. The impeller hub 22 is adjoined radially on the outside by an impeller disk 25 in the form of a circular ring. The impeller disk 25 is adjoined radially on the outside by a support ring 26, which overlaps the impeller disk 25 on both sides in the direction of the compressor longitudinal center axis 20. The support ring 26 carries, in a manner distributed in the circumferential direction, a multiplicity of the impeller blades 7, which protrude radially and are arranged in an equidistant manner. The impeller hub 22, the impeller disk 25 and the support ring 26, and the coupling wall 27 are configured as an integral cast part.

In order to connect the impeller 6 to the driveshaft 4 for conjoint rotation, use is made of a separate coupling device 29. The coupling device 29 comprises a first bushing-type coupling part 30, which sits on the driveshaft 4 in the assembled state and is connected to the latter for conjoint rotation via a feather key connection. For this purpose, a feather key 31 has been inserted circumferentially into the driveshaft 4, said feather key 31 protruding radially outwardly with respect to the driveshaft 4. The feather key 31 engages in a form-fitting manner in an inner, axial feather keyway 32 in the first coupling part 30. The first coupling part 30 also has a radially protruding annular wall 33 and first form-fitting bodies 34 that protrude from the annular wall 33 in the direction of the driveshaft longitudinal center axis 5 and compressor longitudinal center axis 20, respectively. The first form-fitting bodies 34 are arranged in an equidistant manner around the longitudinal center axis 5 or 20, respectively.

Furthermore, the coupling device 29 has a second coupling part 35, which is substantially star-shaped. The second coupling part 35 has an annular body 36 and second form-fitting bodies 37 that protrude radially from the annular body 36. The second form-fitting bodies 37 are arranged in an equidistant manner on the annular body 36.

In the assembled state of the coupling device 29, the first and second form-fitting bodies 34, 37 engage in one another in a form-fitting manner, such that a rotary movement and a torque are transmissible from the first coupling part 30 to the second coupling part 35 by the driveshaft 4. The first and second form-fitting bodies 34, 37 furthermore engage in a form-fitting manner in the coupling wall 27 and in the form-fitting cutouts 28 in the coupling wall 27, respectively, with the result that the rotary movement and the torque are transmissible from the drive 3 to the impeller 6. The driveshaft 4 engages in the impeller 6 but does not pass through the latter. It ends at a distance from the coupling wall 27.

The impeller 6 is mounted in the compressor housing 2 in a rotatable or rotationally drivable manner via a rolling bearing apparatus 38. The rolling bearing apparatus 38 comprises a first rolling bearing device 39 and a second rolling bearing device 40, which are embodied identically. Each rolling bearing device 39, 40 has an inner ring 41 with an inside diameter DI and an outer ring 42, and rolling bodies 43 arranged in between, which are arranged in a corresponding cage 62. The inner ring 41 and outer ring 42 of each rolling bearing device 39, 40 are each arranged concentrically around the longitudinal center axis 5 or 20. The first rolling bearing device 39 is arranged next to a lateral retaining body 44 of the housing body 8, while the second rolling bearing device 40 bears against the cover body 18 laterally on the inside.

In the assembled state of the side channel compressor arrangement, the first rolling bearing device 39 sits with its inner ring 41 directly on the drive-side impeller bearing surface 24, while the second rolling bearing device 40 sits with its inner ring 41 directly on the cover-side impeller bearing surface 24. Expediently, the inner rings 41 are arranged on the impeller bearing surfaces 24 for conjoint rotation there. Expediently, the inner rings 41 are shrink-fitted on the impeller bearing surfaces 24. Each inner ring 41 expediently has an inside diameter DI which is about 50% larger than an outside diameter DA of an adjacent portion of the driveshaft 4. The impeller bearing surfaces 24 and the inner rings 41 are in this case arranged in a manner radially spaced apart from the driveshaft 4. They encircle the driveshaft 4 in a radially spaced-apart manner.

The outer ring 42 of the first rolling bearing device 39 is accommodated in the first hub 10 and sits in the first compressor-housing bearing surface 11. The outer ring 42 of the second rolling bearing device 40 is accommodated in the second hub 14 and sits in the second compressor-housing bearing surface 15. Expediently, the outer rings 42 are connected to the respective compressor-housing bearing surfaces 11 and 15 for conjoint rotation.

Between the rolling bearing devices 39, 40, the impeller disk 25 extends radially outwardly.

During operation, the driveshaft 4 is set in rotation by the drive 3, this ultimately also resulting in a corresponding rotation of the impeller 6 on account of the coupling to the coupling device 29. The impeller blades 7 sweeping past the gas inlet opening 21 draw the gas to be compressed into the side channel 19 via the gas inlet opening 21. They accelerate the gas located in the side channel 19 in the direction of revolution of the impeller 6. In the process, the gas is enclosed in cells, which are bounded internally by the support ring 26 and circumferentially by adjacent impeller blades 7. At the end of the revolution, the impeller blades 7 expel the compressed gas out of the side channel 19 again via the gas outlet opening. It has in the process covered an angular path of about 300° in the compressor 1. The interrupter prevents the gas transported by the impeller 6 from being transported onward to the gas inlet opening 21 from the gas outlet opening within the side channel 19.

In contrast to conventional compressor arrangements, in which the impellers of the compressors sit on the driveshaft of the drive, in this case, the rolling bearing apparatus 39 has been substantially enlarged in order to decouple them from the driveshaft.

The expressions “axial” and “radial” used herein relate to the longitudinal center axis 5 and 20, respectively, which are aligned or coincide with one another.

In the following text, a second embodiment is described with reference to FIGS. 3 and 4. Identical parts have the same reference signs as in the previous embodiment, to the description of which reference is made. Structurally different, but functionally equivalent parts have the same reference signs with a postposed “a”.

Compared with the first embodiment, the compressor 1 a is embodied differently here. In contrast to the first embodiment, in this compressor 1 a, there are two sealing rings 45 and 46, respectively. The sealing rings 45, 46, located opposite one another, bear in a sealing manner against the impeller disk 25. Furthermore, they bear in a sealing manner against the respective impeller bearing surface 24 a.

In order to accommodate the respective sealing ring 45 and 46, the impeller hub 22 a is extended in the case of the impeller 6 a. Compared with the first embodiment, the impeller hub bodies 23 a are thus also axially extended.

The compressor housing 2 a is also embodied differently than in the first embodiment. The housing body 8 a has a corresponding receptacle for receiving the first sealing ring 45. To this end, the retaining body 44 a is arranged in a correspondingly axially offset manner.

Furthermore, instead of the integral cover body, a separate cover body 18 a is present, which is connectable to the actual housing cover 9 a. Formed in the cover body 18 a is the second compressor-housing bearing surface 15 a.

In the following text, a third embodiment is described with reference to FIGS. 5 and 6. Identical parts have the same reference signs as in the first embodiment, to the description of which reference is made. Structurally different, but functionally equivalent parts have the same reference signs with a postposed “b”.

This embodiment differs from the first embodiment by the compressor 1 b. In particular, the coupling between the driveshaft 4 and the impeller 6 b is configured differently. In this case, there is magnetic coupling.

To this end, the coupling device 29 b has a bushing-type first coupling part 30 b with circumferentially arranged, first permanent magnets 47. The first permanent magnets 47 are arranged overall in a cylindrical manner. The first coupling part 30 b is again in a feather key connection with the driveshaft 4.

Furthermore, the coupling device 29 b has a second hollow-cylindrical coupling part 35 b, which is received in the now continuous impeller hub 22 b for conjoint rotation and is formed by a multiplicity of second permanent magnets 48. The second permanent magnets 48 are arranged overall in a cylindrical manner.

In the assembled state, the first coupling part 30 b engages in the impeller hub 22 b. The second permanent magnets 48 surround the first permanent magnets 47 and are magnetically connected to the latter, such that a corresponding magnetic field is present. A connection for conjoint rotation is thus created between the impeller 6 b and the coupling device 29 b.

Between the first permanent magnets 47 and the second permanent magnets 48 there extends a guide sleeve 49 made of a magnetizable material, or a material that does not impair the magnetic field between the first permanent magnets 47 and the second permanent magnets 48.

In the following text, a fourth embodiment is described with reference to FIGS. 7 and 8. Identical parts have the same reference signs as in the first embodiment, to the description of which reference is made. Structurally different, but functionally equivalent parts have the same reference signs with a postposed “c”.

In this embodiment, the compressor arrangement is a two-stage compressor arrangement and comprises two compressors 1 c, which are arranged alongside one another and are embodied in principle in an identical manner. The compressors 1 c differ from the compressor 1 according to the first embodiment.

The drive-side, first compressor 1 c has a compressor housing 2 c with a housing body 8 and a housing cover 9 c. Compared with the first embodiment, the housing cover 9 c has a through-opening 50 in the cover body 18 c. Furthermore, the housing cover 9 c has, on the outside of its end face, an axially protruding first connection ring 51 and a planar first connection face 52 adjoining the latter radially on the outside.

The coupling wall 27 c of the impeller 6 c of the first compressor 1 c is axially widened compared with the first embodiment.

As in the first embodiment, the coupling device 29 engages in a form-fitting manner in the coupling wall 27 c, with the result that the impeller 6 c of the first compressor 1 c is rotationally drivable.

The second compressor 1 c has a second compressor housing 53, which is similar to the compressor housing 2 c of the first compressor 1 c. A second housing body 54 is present, which, in contrast to the housing body 8 of the first compressor 1 c, has a planar second connection face 55 for connection in a sealed manner to the first connection face 52 of the housing cover 9 c of the first compressor 1 c. The second housing body 54 of the second compressor 1 c furthermore has an annular shoulder 56, in which the first connection ring 51 of the first compressor 1 c engages in a form-fitting manner in the assembled state of the compressor arrangement.

A second housing cover 57 of the second compressor 1 c has, in contrast to the housing cover 9 c of the first compressor 1 c, a closed cover body 18.

The second impeller 6 c of the second compressor 1 c is embodied in a manner corresponding to the impeller 6 c of the first compressor 1 c. It is mounted in the second compressor housing 53 in a manner corresponding to the first impeller 6 c of the first compressor 1 c.

The two impellers 6 c are connected together for conjoint rotation, in this case in a form-fitting manner. For this purpose, a second coupling device 58 is provided, which is similar to the coupling device 29 of the first embodiment. Again, there is a bushing-type first coupling part 59, which bears an annular wall 60 at each end, however. Form-fitting bodies 61 protrude axially in opposite directions from each annular wall 60.

The form-fitting bodies 61 of each annular wall 60 are connected again to a star-shaped second coupling part 35 for conjoint rotation. The form-fitting bodies 61 facing the drive 3 and the associated second coupling part 35 engage in the first impeller 6 c of the first compressor 1 c in a form-fitting manner, while the form-fitting bodies 61 facing away from the drive 3 and the associated second coupling part 35 engage in the second impeller 6 c of the second compressor 1 c in a form-fitting manner.

A torque delivered by the drive 3 and a corresponding rotary movement are thus transmitted from the impeller 6 c of the first compressor to the second impeller 6 c of the second compressor 1 c via the second coupling device 58.

Combinations of the individual embodiments are possible. 

1. A compressor arrangement for compressing a gas, comprising a) a drive having a rotationally drivable driveshaft, and b) at least one compressor, which has i) a compressor housing, ii) at least one gas inlet opening formed in the compressor housing, iii) at least one gas outlet opening formed in the compressor housing, said gas outlet opening being in flow connection with the at least one gas inlet opening, iv) at least one rotationally drivable impeller, arranged in the compressor housing and connected to the driveshaft for conjoint rotation, for delivering the gas from the at least one gas inlet opening to the at least one gas outlet opening, and v) at least one bearing apparatus for supporting the at least one impeller, wherein the at least one bearing apparatus is arranged on the compressor housing, and is arranged on the at least one impeller.
 2. The compressor arrangement as claimed in claim 1, characterized in that the at least one bearing apparatus is embodied as a rolling bearing apparatus.
 3. The compressor arrangement as claimed in claim 1, characterized in that the at least one bearing apparatus comprises a first bearing body arranged on the compressor housing and a second bearing body, which is arranged on the at least one impeller.
 4. The compressor arrangement as claimed in claim 1, characterized in that the at least one bearing apparatus is arranged in a manner radially spaced apart from the driveshaft.
 5. The compressor arrangement as claimed in claim 1, characterized in that the at least one bearing apparatus has an internal dimension (DI) which is much greater than an external dimension (DA) of an adjacent portion of the driveshaft.
 6. The compressor arrangement as claimed in claim 1, characterized in that the compressor housing has at least one inwardly facing compressor-housing bearing surface for at least regionally arranging on the at least one bearing apparatus.
 7. The compressor arrangement as claimed in claim 1, characterized in that the at least one impeller has at least one outwardly facing impeller bearing surface for at least regionally arranging on the at least one bearing apparatus.
 8. The compressor arrangement as claimed in claim 1, characterized in that the at least one bearing apparatus comprises two bearing devices, wherein at least one impeller extends radially between the two bearing devices.
 9. The compressor arrangement as claimed in claim 1, characterized by at least one coupling device, which is connected to the driveshaft and at least one impeller for conjoint rotation.
 10. The compressor arrangement as claimed in claim 9, characterized in that the at least one bearing apparatus extends at least partially around the at least one coupling device.
 11. The compressor arrangement as claimed in claim 1, characterized in that the at least one coupling device has a first coupling part that is connected to the driveshaft for conjoint rotation and a second coupling part that is connected to the first coupling part for conjoint rotation, wherein the first coupling part and/or the second coupling part is connected to the at least one impeller for conjoint rotation, wherein preferably the first coupling part and the second coupling part are connected together in a form-fitting manner in the assembled state.
 12. The compressor arrangement as claimed in claim 1, characterized in that the at least one coupling device and the at least one impeller are connected together for conjoint rotation by means of magnetic force, wherein preferably the at least one coupling device comprises at least one first magnet and at least one impeller comprises at least one second magnet, which is connected to the at least one first magnet for conjoint rotation.
 13. The compressor arrangement as claimed in claim 1, characterized by at least one seal arrangement which bears against the compressor housing and the at least one impeller in a sealing manner.
 14. The compressor arrangement as claimed in claim 1, characterized by at least two impellers, wherein each impeller a) is connected to the driveshaft for conjoint rotation, and b) is mounted in a rotationally drivable manner via at least one bearing apparatus, which i) is arranged on the compressor housing, and ii) is arranged on the at least one impeller. 